Pests and Pesticides in Agriculture (2024)

Learning Objective

A pest is an organism living and growing where they are not wanted and can cause damage to plants, humans, structures, and other creatures, including crops that are grown for food. Students will learn about different types of pests and the damage they cause, including an example of pests on corn. Integrated pest management is when different controls methods are used to manage pests, including chemical controls, which must be used responsibly by farmers on crops and by adults around the home.

Suggested Audience

• 3^rd - 5^th Grade

Suggested Time

Each section of the lesson could be covered in one thirty minute class period. Another option is to summarize the main points of the entire lesson in a forty-five to sixty minute class period. Determine what is best for your class depending on students and available time.

Pennsylvania Academic Standards

• Environment and Ecology 4.4.4.B. -- Describe how humans rely on the food and fiber system
• Environment and Ecology 4.5.3.B. -- Define the term pest and identify various plants and animals the humans may call pests
• Environment and Ecology 4.5.4.B. -- Determine circ*mstances that cause humans to identify an organism as a pest
• English Language Arts CC.1.5.4.C. -- Identify the reasons and evidence a speaker provides to support particular points
• Health, Safety, & Physical Education 10.5.3.A. -- Recognize and use basic movement skills and concepts

Lesson Instructions

Section 1: Pests

Pests are organisms living and growing where they are not wanted and can cause damage to plants, humans, structures, and other creatures.

Pests can be broken into four main categories

1. Vertebrate Pests
   Have a backbone. Examples: Rodents, birds, reptiles, and other mammals
2. Invertebrate Pests
   No backbone. Examples: Insets, spiders, ticks, slugs
3. Weeds
   Any plant growing out of place.
4. Diseases
   Fungi, bacteria, viruses, and other microorganisms.

Discussion

Have students share an example of a pest, why the organism is a pest, and whether the pest is a vertebrate, invertebrate, weed, or disease.

Pests can pose a serious threat to a food supply. A major food crop is corn, which supplies humans with food that we eat, food for animals, and corn ethanol used for fuel. There are many pests to corn, including vertebrates, invertebrates, weeds, and diseases.

Examples

Vertebrate Pests
Deer, raccoons, rabbits, birds, and other creatures can eat the corn crop at various stages of the growth of the corn.

Invertebrate Pests
Cutworms are the larvae of what will eventually become a moth. In the larvae stage, the cutworms live near or below the soil surface. The cutworms feed on corn that has recently emerged from the ground, chewing off the small corn sprouts causing damage that often appears as if the corn has been "cut." Other invertebrate pests can attack corn at various stages of growth.

Weeds
Besides the corn plants, any other plant in the corn field could be considered weeds, as these other plants are competing for water, sunlight, and nutrients with the corn.

Diseases
Blights, rusts, and leaf spots are just a few diseases that can affect corn. Corn blight is caused by fungal pathogens, with lesions developing on the lower leaves and possibly spreading to the whole plant. The corn experiences decreased photosynthesis, with the corn leaves eventually turning brown.

A Step Further: Draw or print images of corn pests as a visual for students.

Activity

Pests in the Corn

Activity Prep

In case a student is unable to participate in the activity, print or write "Vertebrate Pests" on sign or sheet of paper, "Invertebrate Pests" on a second sheet, "Weeds" on a third sheet, and "Diseases" on a fourth sheet. A student unable to participate in the activity can help by displaying the sign once the pest damage is discussed in the activity.

Activity Facilitation

Students will be moving in the activity as they explore how pests can affect corn. As the facilitator, you will be explaining what is happening to the corn and demonstrating the movement, as the students follow you. Students will be standing for the activity and should have some space around them so they can move in the activity and not bump into other students.

1. The activity begins with students becoming the corn seed planted in the ground. Have students crouch down, with their feet on the ground. As the corn seed begins to grow and rises up out of the ground, have students begin to stand. Before standing up completely, tell students to put their head to the left side. Explain that a pest has just attacked the corn. Ask students what pest it was. Response would be a cutworm, which eats the corn as a small corn sprout. We had a pest problem and the corn did not grow.
2. Tell students we are going to try again to grow corn, so assume the first position of the corn seed, crouching down with feet on the ground. As the corn seed begins to grow and rises up out of the ground, have students begin to stand. Have them stand the whole way up, but keeping their arms crossed over their chest. Explain how another plant is growing right beside them. That plant is getting bigger, taking all the water, sunlight, and nutrients. The corn cannot grow anymore, so their arms have to stay crossed over their chest. Explain that a pest has just attacked the corn. Ask students what pest it was. Response would be a weed, another plant that is growing out of place. We had a pest problem and the corn did not grow.
3. Tell students we are going to try again to grow corn, so assume the first position of the corn seed, crouching down with feet on the ground. As the corn seed begins to grow and rises up out of the ground, have students begin to stand. Have them stand the whole way up and put elbows up and out, replicating the leaves of the corn. Explain to the students that brown spots are beginning to appear on the leaves. The spots are getting bigger. Have the students slowly being to drop their elbows back down to their bodies, as the corn leaves are browning and the corn cannot make its own food. Explain that a pest has just attacked the corn. Ask students what pest it was. Response would be disease, such as leaf blight when fungal spores landed on the corn, lesions spread, and the corn could no longer make its own food. We had a pest problem and the corn did not grow.
4. Tell students we are going to try again to grow corn, so assume the first position of the corn seed, crouching down with feet on the ground. As the corn seed begins to grow and rises up out of the ground, have students begin to stand. Have them stand the whole way up and put elbows up and out, replicating the leaves of the corn. Stand for a moment in that position, as the corn is growing, taking in water, sunlight and nutrients. Explain to students that something is in the corn field, eating the corn leaves. Have them bring one arm down by their side and then bring down the other arm. Explain that a pest has just attacked the corn. Ask students what pest it was. Response would be a vertebrate pest, such as deer. We had a pest problem and the corn did not grow.
5. Tell students we are going to try one more time to grow corn, so assume the first position of the corn seed, crouching down with feet on the ground. As the corn seed begins to grow and rises up out of the ground, have students begin to stand. Have them stand the whole way up and put elbows up and out, replicating the leaves of the corn. Stand for a moment in that position, as the corn is growing, taking in water, sunlight and nutrients. Have students make fists with their hands to replicate the ears of corn. Explain that there was no pest problem! The corn has successfully grown and can be harvested for use as food and fuel.

Discussion

Explain to students that farmers have many pest problems to watch for when growing corn. Ask students what else might affect corn growth. Responses could include frost, drought, hail, and other weather factors. Like any living organism, corn needs nutrients, water, and a healthy environment to grow; this includes sunlight, healthy soil, and pest management.

Section 2: Integrated Pest Management

To control pests both in our homes and on crops, integrated pest management is a strategy that we can use. Integrated pest management is a process that uses different ways to control pests. The steps include 1) Identify the Pest, 2) Monitor Pest Activity, 3) Choose Control Methods, and 4) Evaluate Results.

A Step Further

Print or write "Identify the Pest" on a sign or sheet of paper, "Monitor Pest Activity" on a second sheet, "Choose Control Methods" on a third sheet, and "Evaluate Results" on a fourth sheet. Prior to sharing the correct order of the steps, have four volunteers hold the signs (not in the correct order) and have the group hypothesize what is the correct order for the steps of Integrated Pest Management.

The control methods in integrated pest management include cultural, biological, mechanical, and chemical. As homeowners use a combination of ways to control pests, farmers also use these methods but in different ways. Depending on the audience, explain control methods from the example of a mouse in the house and/or the example of control pests in agriculture.

Cultural control means changing the environment. In the home, that can be cleaning up food and keeping the area clean. In agriculture, that means crop rotation in fields, managing the soil for optimum soil health, and choosing resistant varieties, such as corn hybrids that are resistant to a pest.

Mechanical control means physical objects such as traps, machines, and devices. In the home, a mouse trap may be used. In agriculture, plowing and tillage of the soil might be used to control weeds and traps are also used for monitoring insects and catching pests.

Biological controls are natural enemies of the pests, such as animals and other creatures. In the home, that could be a cat that eats the mouse. In agriculture, that can be predators like lady beetles and lacewings, or parasites like wasps and flies.

Chemical controls are poisonous to the pests, such as sprays, dusts, and baits. In the home, mouse bait (a rodenticide) might be used. In agriculture, pesticides are sometimes used to control various pests to crops.

Section 3: Chemical Safety

Chemical control is a control option in integrated pest management. In agriculture, if farmers are applying pesticides to control pests, they often have to be certified pesticide applicator, which means they have to take a test to obtain their pesticide license and attend meetings to learn more information about applying pesticides safely. When farmers use pesticides, they have to read the pesticide label for instructions, wear necessary personal protective equipment, and apply pesticides at labeled rates. By following the pesticide label, they can ensure they are applying the right amount, as applying too much pesticide could severely damage the crop. They also must keep records of their pesticide application and have a safe place to store pesticide products on the farm.

A Step Further

Have images or examples of materials that are used by pesticide applicators, such as a pesticide manual, pesticide labels, personal protective equipment, calibration cups, recordkeeping forms, or pesticide storage sign.

Pesticide applicators must be responsible when using pesticide products. They sometimes choose to use pesticides as pests would otherwise destroy their crop, but they must be good stewards to protect the environment, their families and other people, and also themselves.

Pesticides must also be used responsibly in the home. If you are using any product to control pests, whether they are vertebrates, invertebrates, weeds, or diseases, pesticides must be used responsibly. Examples of pesticide products in our home include rodenticide bait to control mice, flea control for pets, insect repellents, any cleaning product that controls bacteria, viruses, and other disease, and more. Just like the farmers, homeowners should always read the label and follow the label instructions. Pesticides should be stored properly, out of reach of children, when not in use. Mr. Yuk can be placed on the products to alert family members of a potential poisonous product.

Discussion

Have students share about any pesticides or other potentially poisonous products that might be around their homes. Discuss how those products are used, where the products should be stored when not in use, and what can be done to help keep homes safe from accidental poisonings.

A Step Further

Visit the Penn State Pesticide Education Program website for more resources, including printable activity sheets on integrated pest management and poison safety. You can also download a copy of this Lesson Plan.

For More Information

The Penn State Pesticide Education Program strives to educate all pesticide applicators and users across the Commonwealth about pest management alternatives, including the safe, proper, and legal use of pesticides. The program promotes responsible decision-making, which will protect pesticide users, public health, plant and animal health, and the environment.